Electronic devices and optical components use a metal structure comprising a substrate and a patterned metal body or film. Several patterning methods are known for forming the predetermined pattern, and representative methods include the one using a photoresist, the one using contact printing, the one using ink jet printing, and the one using scanning probe microscope.
In a representative method, irregularity-forming layers having different etching speed and a resist pattern are disposed on the substrate and a structure having surface irregularities is formed by photolithographic and etching process (see, for example, Japanese Published Unexamined Patent Application No. Hei 7-198918). Another method known in the art is a method wherein a metal structure is formed by forming a layer of resist material on the surface of an article, forming a self-assembled monolayer on the layer of resist material by using a large-area stamp, etching the layer of resist material, and etching or plating the surface of the article (see, for example, Japanese Published Unexamined Patent Application No. Hei 10-12545).
Also known is a method wherein fine grooves or pits having an opening of 5 to 100 μm are formed at a regular interval by laser beam irradiation (see, for example, Japanese Published Unexamined Patent Application No. 2000-158157).
The photolithographic process requires quite a number of steps such as formation of the resist film, exposure, development, and the like and this invites an increased cost of the apparatus and chemicals used, and use of a large quantity of chemicals invites risk of environmental pollution by the discarding of the used chemicals.
The etching using a resist film is associated with the problems of an increased cost by the use of the resist film and the environmental pollution due to the discarding of the chemicals used in the process.
The method of irradiating the laser beam has the problem that a long time is required in the case of a structure having a large surface area since the area irradiated by the laser beam is limited.
In view of the situation as described above, an object of the present invention is to provide a method for producing a metal structure which is capable of forming a metal film of predetermined fine pattern in a reduced number of steps. Another object of the present invention is to provide a metal structure produced by such method.